| 摘要 |
PURPOSE:To obtain enough slipperiness, runability and plainness and to obtain a film with excellent wear resistance by placing an aqueous liq. film on the surface of a drum in a method for preparing a polyester film. CONSTITUTION:A polyester film is prepd. by bringing a molten polyester sheet contg. 0.01-5.0wt.% inert inorg. particle into tight contact with the surface of a cooling drum while static electricity is applied and an aqueous liq. film is placed on the surface of the drum. A film with more excellent wear resistance is obtd. by using a spherical particle with a particle diameter ratio of the inert inorg. particle of 1.0-1.3. In addition, the mean particle diameter of the inert inorg. particle is pref. 10-500nm and the wear-resistance becomes poor if the loading is less than or more than 0.01-5.0wt.%. As the method for placing an aqueous liq. film, a moisture condensation method is pref. as a stable liq. film is obtd. when the apparent liq. film thickness is 3mum or thin or the surface of the cooling drum is a mirror surface chromium plating. It is pref. that the max. diameter of the water droplet is 50mum or smaller and the number thereof is 100-1,000/0.1mm<2> in the moisture condensation method. |
